Mon, 12 Mar 2012 14:59:00 -0700
7147724: G1: hang in SurrogateLockerThread::manipulatePLL
Summary: Attempting to initiate a marking cycle when allocating a humongous object can, if a marking cycle is successfully initiated by another thread, result in the allocating thread spinning until the marking cycle is complete. Eliminate a deadlock between the main ConcurrentMarkThread, the SurrogateLocker thread, the VM thread, and a mutator thread waiting on the SecondaryFreeList_lock (while free regions are going to become available) by not manipulating the pending list lock during the prologue and epilogue of the cleanup pause.
Reviewed-by: brutisso, jcoomes, tonyp
ysr@777 | 1 | /* |
never@3499 | 2 | * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved. |
ysr@777 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
ysr@777 | 4 | * |
ysr@777 | 5 | * This code is free software; you can redistribute it and/or modify it |
ysr@777 | 6 | * under the terms of the GNU General Public License version 2 only, as |
ysr@777 | 7 | * published by the Free Software Foundation. |
ysr@777 | 8 | * |
ysr@777 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
ysr@777 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
ysr@777 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
ysr@777 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
ysr@777 | 13 | * accompanied this code). |
ysr@777 | 14 | * |
ysr@777 | 15 | * You should have received a copy of the GNU General Public License version |
ysr@777 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
ysr@777 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
ysr@777 | 18 | * |
trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
trims@1907 | 21 | * questions. |
ysr@777 | 22 | * |
ysr@777 | 23 | */ |
ysr@777 | 24 | |
stefank@2314 | 25 | #include "precompiled.hpp" |
stefank@2314 | 26 | #include "classfile/javaClasses.hpp" |
stefank@2314 | 27 | #include "classfile/symbolTable.hpp" |
stefank@2314 | 28 | #include "classfile/systemDictionary.hpp" |
stefank@2314 | 29 | #include "classfile/vmSymbols.hpp" |
stefank@2314 | 30 | #include "code/codeCache.hpp" |
stefank@2314 | 31 | #include "code/icBuffer.hpp" |
stefank@2314 | 32 | #include "gc_implementation/g1/g1MarkSweep.hpp" |
stefank@2314 | 33 | #include "memory/gcLocker.hpp" |
stefank@2314 | 34 | #include "memory/genCollectedHeap.hpp" |
stefank@2314 | 35 | #include "memory/modRefBarrierSet.hpp" |
stefank@2314 | 36 | #include "memory/referencePolicy.hpp" |
stefank@2314 | 37 | #include "memory/space.hpp" |
stefank@2314 | 38 | #include "oops/instanceRefKlass.hpp" |
stefank@2314 | 39 | #include "oops/oop.inline.hpp" |
stefank@2314 | 40 | #include "prims/jvmtiExport.hpp" |
stefank@2314 | 41 | #include "runtime/aprofiler.hpp" |
stefank@2314 | 42 | #include "runtime/biasedLocking.hpp" |
stefank@2314 | 43 | #include "runtime/fprofiler.hpp" |
stefank@2314 | 44 | #include "runtime/synchronizer.hpp" |
stefank@2314 | 45 | #include "runtime/thread.hpp" |
stefank@2314 | 46 | #include "runtime/vmThread.hpp" |
stefank@2314 | 47 | #include "utilities/copy.hpp" |
stefank@2314 | 48 | #include "utilities/events.hpp" |
ysr@777 | 49 | |
ysr@777 | 50 | class HeapRegion; |
ysr@777 | 51 | |
ysr@777 | 52 | void G1MarkSweep::invoke_at_safepoint(ReferenceProcessor* rp, |
ysr@777 | 53 | bool clear_all_softrefs) { |
ysr@777 | 54 | assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); |
ysr@777 | 55 | |
jmasa@1822 | 56 | SharedHeap* sh = SharedHeap::heap(); |
jmasa@1822 | 57 | #ifdef ASSERT |
jmasa@1822 | 58 | if (sh->collector_policy()->should_clear_all_soft_refs()) { |
jmasa@1822 | 59 | assert(clear_all_softrefs, "Policy should have been checked earler"); |
jmasa@1822 | 60 | } |
jmasa@1822 | 61 | #endif |
ysr@777 | 62 | // hook up weak ref data so it can be used during Mark-Sweep |
ysr@777 | 63 | assert(GenMarkSweep::ref_processor() == NULL, "no stomping"); |
ysr@888 | 64 | assert(rp != NULL, "should be non-NULL"); |
johnc@3175 | 65 | assert(rp == G1CollectedHeap::heap()->ref_processor_stw(), "Precondition"); |
johnc@3175 | 66 | |
ysr@777 | 67 | GenMarkSweep::_ref_processor = rp; |
ysr@892 | 68 | rp->setup_policy(clear_all_softrefs); |
ysr@777 | 69 | |
ysr@777 | 70 | // When collecting the permanent generation methodOops may be moving, |
ysr@777 | 71 | // so we either have to flush all bcp data or convert it into bci. |
ysr@777 | 72 | CodeCache::gc_prologue(); |
ysr@777 | 73 | Threads::gc_prologue(); |
ysr@777 | 74 | |
ysr@777 | 75 | // Increment the invocation count for the permanent generation, since it is |
ysr@777 | 76 | // implicitly collected whenever we do a full mark sweep collection. |
ysr@777 | 77 | sh->perm_gen()->stat_record()->invocations++; |
ysr@777 | 78 | |
ysr@777 | 79 | bool marked_for_unloading = false; |
ysr@777 | 80 | |
ysr@777 | 81 | allocate_stacks(); |
ysr@777 | 82 | |
iveresov@793 | 83 | // We should save the marks of the currently locked biased monitors. |
iveresov@793 | 84 | // The marking doesn't preserve the marks of biased objects. |
iveresov@793 | 85 | BiasedLocking::preserve_marks(); |
iveresov@793 | 86 | |
ysr@777 | 87 | mark_sweep_phase1(marked_for_unloading, clear_all_softrefs); |
ysr@777 | 88 | |
ysr@777 | 89 | mark_sweep_phase2(); |
ysr@777 | 90 | |
ysr@777 | 91 | // Don't add any more derived pointers during phase3 |
ysr@777 | 92 | COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); |
ysr@777 | 93 | |
ysr@777 | 94 | mark_sweep_phase3(); |
ysr@777 | 95 | |
ysr@777 | 96 | mark_sweep_phase4(); |
ysr@777 | 97 | |
ysr@777 | 98 | GenMarkSweep::restore_marks(); |
iveresov@793 | 99 | BiasedLocking::restore_marks(); |
ysr@777 | 100 | GenMarkSweep::deallocate_stacks(); |
ysr@777 | 101 | |
ysr@777 | 102 | // We must invalidate the perm-gen rs, so that it gets rebuilt. |
ysr@777 | 103 | GenRemSet* rs = sh->rem_set(); |
ysr@777 | 104 | rs->invalidate(sh->perm_gen()->used_region(), true /*whole_heap*/); |
ysr@777 | 105 | |
ysr@777 | 106 | // "free at last gc" is calculated from these. |
ysr@777 | 107 | // CHF: cheating for now!!! |
ysr@777 | 108 | // Universe::set_heap_capacity_at_last_gc(Universe::heap()->capacity()); |
ysr@777 | 109 | // Universe::set_heap_used_at_last_gc(Universe::heap()->used()); |
ysr@777 | 110 | |
ysr@777 | 111 | Threads::gc_epilogue(); |
ysr@777 | 112 | CodeCache::gc_epilogue(); |
kamg@2467 | 113 | JvmtiExport::gc_epilogue(); |
ysr@777 | 114 | |
ysr@777 | 115 | // refs processing: clean slate |
ysr@777 | 116 | GenMarkSweep::_ref_processor = NULL; |
ysr@777 | 117 | } |
ysr@777 | 118 | |
ysr@777 | 119 | |
ysr@777 | 120 | void G1MarkSweep::allocate_stacks() { |
ysr@777 | 121 | GenMarkSweep::_preserved_count_max = 0; |
ysr@777 | 122 | GenMarkSweep::_preserved_marks = NULL; |
ysr@777 | 123 | GenMarkSweep::_preserved_count = 0; |
ysr@777 | 124 | } |
ysr@777 | 125 | |
ysr@777 | 126 | void G1MarkSweep::mark_sweep_phase1(bool& marked_for_unloading, |
ysr@777 | 127 | bool clear_all_softrefs) { |
ysr@777 | 128 | // Recursively traverse all live objects and mark them |
ysr@777 | 129 | TraceTime tm("phase 1", PrintGC && Verbose, true, gclog_or_tty); |
ysr@777 | 130 | GenMarkSweep::trace(" 1"); |
ysr@777 | 131 | |
ysr@777 | 132 | SharedHeap* sh = SharedHeap::heap(); |
ysr@777 | 133 | |
jrose@1424 | 134 | sh->process_strong_roots(true, // activeate StrongRootsScope |
jrose@1424 | 135 | true, // Collecting permanent generation. |
ysr@777 | 136 | SharedHeap::SO_SystemClasses, |
ysr@777 | 137 | &GenMarkSweep::follow_root_closure, |
jrose@1424 | 138 | &GenMarkSweep::follow_code_root_closure, |
ysr@777 | 139 | &GenMarkSweep::follow_root_closure); |
ysr@777 | 140 | |
ysr@777 | 141 | // Process reference objects found during marking |
ysr@888 | 142 | ReferenceProcessor* rp = GenMarkSweep::ref_processor(); |
johnc@3175 | 143 | assert(rp == G1CollectedHeap::heap()->ref_processor_stw(), "Sanity"); |
johnc@3175 | 144 | |
ysr@892 | 145 | rp->setup_policy(clear_all_softrefs); |
ysr@888 | 146 | rp->process_discovered_references(&GenMarkSweep::is_alive, |
ysr@888 | 147 | &GenMarkSweep::keep_alive, |
ysr@888 | 148 | &GenMarkSweep::follow_stack_closure, |
ysr@888 | 149 | NULL); |
ysr@777 | 150 | |
ysr@777 | 151 | // Follow system dictionary roots and unload classes |
ysr@777 | 152 | bool purged_class = SystemDictionary::do_unloading(&GenMarkSweep::is_alive); |
jcoomes@2191 | 153 | assert(GenMarkSweep::_marking_stack.is_empty(), |
ysr@777 | 154 | "stack should be empty by now"); |
ysr@777 | 155 | |
ysr@777 | 156 | // Follow code cache roots (has to be done after system dictionary, |
ysr@777 | 157 | // assumes all live klasses are marked) |
ysr@777 | 158 | CodeCache::do_unloading(&GenMarkSweep::is_alive, |
ysr@777 | 159 | &GenMarkSweep::keep_alive, |
ysr@777 | 160 | purged_class); |
ysr@1376 | 161 | GenMarkSweep::follow_stack(); |
ysr@777 | 162 | |
ysr@777 | 163 | // Update subklass/sibling/implementor links of live klasses |
ysr@777 | 164 | GenMarkSweep::follow_weak_klass_links(); |
jcoomes@2191 | 165 | assert(GenMarkSweep::_marking_stack.is_empty(), |
ysr@777 | 166 | "stack should be empty by now"); |
ysr@777 | 167 | |
ysr@1376 | 168 | // Visit memoized MDO's and clear any unmarked weak refs |
ysr@1376 | 169 | GenMarkSweep::follow_mdo_weak_refs(); |
jcoomes@2191 | 170 | assert(GenMarkSweep::_marking_stack.is_empty(), "just drained"); |
ysr@1376 | 171 | |
coleenp@2497 | 172 | // Visit interned string tables and delete unmarked oops |
ysr@777 | 173 | StringTable::unlink(&GenMarkSweep::is_alive); |
coleenp@2497 | 174 | // Clean up unreferenced symbols in symbol table. |
coleenp@2497 | 175 | SymbolTable::unlink(); |
ysr@777 | 176 | |
jcoomes@2191 | 177 | assert(GenMarkSweep::_marking_stack.is_empty(), |
ysr@777 | 178 | "stack should be empty by now"); |
johnc@2969 | 179 | |
johnc@2969 | 180 | if (VerifyDuringGC) { |
johnc@2969 | 181 | HandleMark hm; // handle scope |
johnc@2969 | 182 | COMPILER2_PRESENT(DerivedPointerTableDeactivate dpt_deact); |
johnc@2969 | 183 | gclog_or_tty->print(" VerifyDuringGC:(full)[Verifying "); |
johnc@2969 | 184 | Universe::heap()->prepare_for_verify(); |
johnc@2969 | 185 | // Note: we can verify only the heap here. When an object is |
johnc@2969 | 186 | // marked, the previous value of the mark word (including |
johnc@2969 | 187 | // identity hash values, ages, etc) is preserved, and the mark |
johnc@2969 | 188 | // word is set to markOop::marked_value - effectively removing |
johnc@2969 | 189 | // any hash values from the mark word. These hash values are |
johnc@2969 | 190 | // used when verifying the dictionaries and so removing them |
johnc@2969 | 191 | // from the mark word can make verification of the dictionaries |
johnc@2969 | 192 | // fail. At the end of the GC, the orginal mark word values |
johnc@2969 | 193 | // (including hash values) are restored to the appropriate |
johnc@2969 | 194 | // objects. |
johnc@2969 | 195 | Universe::heap()->verify(/* allow dirty */ true, |
johnc@2969 | 196 | /* silent */ false, |
johnc@2969 | 197 | /* option */ VerifyOption_G1UseMarkWord); |
johnc@2969 | 198 | |
johnc@2969 | 199 | G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
johnc@2969 | 200 | gclog_or_tty->print_cr("]"); |
johnc@2969 | 201 | } |
ysr@777 | 202 | } |
ysr@777 | 203 | |
ysr@777 | 204 | class G1PrepareCompactClosure: public HeapRegionClosure { |
tonyp@2472 | 205 | G1CollectedHeap* _g1h; |
ysr@777 | 206 | ModRefBarrierSet* _mrbs; |
ysr@777 | 207 | CompactPoint _cp; |
tonyp@2472 | 208 | HumongousRegionSet _humongous_proxy_set; |
ysr@777 | 209 | |
ysr@777 | 210 | void free_humongous_region(HeapRegion* hr) { |
ysr@777 | 211 | HeapWord* end = hr->end(); |
tonyp@2643 | 212 | size_t dummy_pre_used; |
tonyp@2643 | 213 | FreeRegionList dummy_free_list("Dummy Free List for G1MarkSweep"); |
tonyp@2643 | 214 | |
ysr@777 | 215 | assert(hr->startsHumongous(), |
ysr@777 | 216 | "Only the start of a humongous region should be freed."); |
tonyp@2643 | 217 | _g1h->free_humongous_region(hr, &dummy_pre_used, &dummy_free_list, |
tonyp@2472 | 218 | &_humongous_proxy_set, false /* par */); |
ysr@777 | 219 | hr->prepare_for_compaction(&_cp); |
ysr@777 | 220 | // Also clear the part of the card table that will be unused after |
ysr@777 | 221 | // compaction. |
tonyp@2472 | 222 | _mrbs->clear(MemRegion(hr->compaction_top(), end)); |
tonyp@2643 | 223 | dummy_free_list.remove_all(); |
ysr@777 | 224 | } |
ysr@777 | 225 | |
ysr@777 | 226 | public: |
tonyp@2472 | 227 | G1PrepareCompactClosure(CompactibleSpace* cs) |
tonyp@2472 | 228 | : _g1h(G1CollectedHeap::heap()), |
tonyp@2472 | 229 | _mrbs(G1CollectedHeap::heap()->mr_bs()), |
ysr@777 | 230 | _cp(NULL, cs, cs->initialize_threshold()), |
tonyp@2472 | 231 | _humongous_proxy_set("G1MarkSweep Humongous Proxy Set") { } |
tonyp@2472 | 232 | |
tonyp@2472 | 233 | void update_sets() { |
tonyp@2472 | 234 | // We'll recalculate total used bytes and recreate the free list |
tonyp@2472 | 235 | // at the end of the GC, so no point in updating those values here. |
tonyp@2472 | 236 | _g1h->update_sets_after_freeing_regions(0, /* pre_used */ |
tonyp@2472 | 237 | NULL, /* free_list */ |
tonyp@3268 | 238 | NULL, /* old_proxy_set */ |
tonyp@2472 | 239 | &_humongous_proxy_set, |
tonyp@2472 | 240 | false /* par */); |
tonyp@2472 | 241 | } |
tonyp@2472 | 242 | |
ysr@777 | 243 | bool doHeapRegion(HeapRegion* hr) { |
ysr@777 | 244 | if (hr->isHumongous()) { |
ysr@777 | 245 | if (hr->startsHumongous()) { |
ysr@777 | 246 | oop obj = oop(hr->bottom()); |
ysr@777 | 247 | if (obj->is_gc_marked()) { |
ysr@777 | 248 | obj->forward_to(obj); |
ysr@777 | 249 | } else { |
ysr@777 | 250 | free_humongous_region(hr); |
ysr@777 | 251 | } |
ysr@777 | 252 | } else { |
ysr@777 | 253 | assert(hr->continuesHumongous(), "Invalid humongous."); |
ysr@777 | 254 | } |
ysr@777 | 255 | } else { |
ysr@777 | 256 | hr->prepare_for_compaction(&_cp); |
ysr@777 | 257 | // Also clear the part of the card table that will be unused after |
ysr@777 | 258 | // compaction. |
ysr@777 | 259 | _mrbs->clear(MemRegion(hr->compaction_top(), hr->end())); |
ysr@777 | 260 | } |
ysr@777 | 261 | return false; |
ysr@777 | 262 | } |
ysr@777 | 263 | }; |
apetrusenko@1112 | 264 | |
apetrusenko@1112 | 265 | // Finds the first HeapRegion. |
ysr@777 | 266 | class FindFirstRegionClosure: public HeapRegionClosure { |
ysr@777 | 267 | HeapRegion* _a_region; |
ysr@777 | 268 | public: |
apetrusenko@1112 | 269 | FindFirstRegionClosure() : _a_region(NULL) {} |
ysr@777 | 270 | bool doHeapRegion(HeapRegion* r) { |
apetrusenko@1112 | 271 | _a_region = r; |
apetrusenko@1112 | 272 | return true; |
ysr@777 | 273 | } |
ysr@777 | 274 | HeapRegion* result() { return _a_region; } |
ysr@777 | 275 | }; |
ysr@777 | 276 | |
ysr@777 | 277 | void G1MarkSweep::mark_sweep_phase2() { |
ysr@777 | 278 | // Now all live objects are marked, compute the new object addresses. |
ysr@777 | 279 | |
ysr@777 | 280 | // It is imperative that we traverse perm_gen LAST. If dead space is |
ysr@777 | 281 | // allowed a range of dead object may get overwritten by a dead int |
ysr@777 | 282 | // array. If perm_gen is not traversed last a klassOop may get |
ysr@777 | 283 | // overwritten. This is fine since it is dead, but if the class has dead |
ysr@777 | 284 | // instances we have to skip them, and in order to find their size we |
ysr@777 | 285 | // need the klassOop! |
ysr@777 | 286 | // |
ysr@777 | 287 | // It is not required that we traverse spaces in the same order in |
ysr@777 | 288 | // phase2, phase3 and phase4, but the ValidateMarkSweep live oops |
ysr@777 | 289 | // tracking expects us to do so. See comment under phase4. |
ysr@777 | 290 | |
ysr@777 | 291 | G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
ysr@777 | 292 | Generation* pg = g1h->perm_gen(); |
ysr@777 | 293 | |
ysr@777 | 294 | TraceTime tm("phase 2", PrintGC && Verbose, true, gclog_or_tty); |
ysr@777 | 295 | GenMarkSweep::trace("2"); |
ysr@777 | 296 | |
apetrusenko@1112 | 297 | FindFirstRegionClosure cl; |
ysr@777 | 298 | g1h->heap_region_iterate(&cl); |
ysr@777 | 299 | HeapRegion *r = cl.result(); |
ysr@777 | 300 | CompactibleSpace* sp = r; |
ysr@777 | 301 | if (r->isHumongous() && oop(r->bottom())->is_gc_marked()) { |
ysr@777 | 302 | sp = r->next_compaction_space(); |
ysr@777 | 303 | } |
ysr@777 | 304 | |
apetrusenko@1112 | 305 | G1PrepareCompactClosure blk(sp); |
ysr@777 | 306 | g1h->heap_region_iterate(&blk); |
tonyp@2472 | 307 | blk.update_sets(); |
ysr@777 | 308 | |
ysr@777 | 309 | CompactPoint perm_cp(pg, NULL, NULL); |
ysr@777 | 310 | pg->prepare_for_compaction(&perm_cp); |
ysr@777 | 311 | } |
ysr@777 | 312 | |
ysr@777 | 313 | class G1AdjustPointersClosure: public HeapRegionClosure { |
ysr@777 | 314 | public: |
ysr@777 | 315 | bool doHeapRegion(HeapRegion* r) { |
ysr@777 | 316 | if (r->isHumongous()) { |
ysr@777 | 317 | if (r->startsHumongous()) { |
ysr@777 | 318 | // We must adjust the pointers on the single H object. |
ysr@777 | 319 | oop obj = oop(r->bottom()); |
ysr@777 | 320 | debug_only(GenMarkSweep::track_interior_pointers(obj)); |
ysr@777 | 321 | // point all the oops to the new location |
ysr@777 | 322 | obj->adjust_pointers(); |
ysr@777 | 323 | debug_only(GenMarkSweep::check_interior_pointers()); |
ysr@777 | 324 | } |
ysr@777 | 325 | } else { |
ysr@777 | 326 | // This really ought to be "as_CompactibleSpace"... |
ysr@777 | 327 | r->adjust_pointers(); |
ysr@777 | 328 | } |
ysr@777 | 329 | return false; |
ysr@777 | 330 | } |
ysr@777 | 331 | }; |
ysr@777 | 332 | |
ysr@777 | 333 | void G1MarkSweep::mark_sweep_phase3() { |
ysr@777 | 334 | G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
ysr@777 | 335 | Generation* pg = g1h->perm_gen(); |
ysr@777 | 336 | |
ysr@777 | 337 | // Adjust the pointers to reflect the new locations |
ysr@777 | 338 | TraceTime tm("phase 3", PrintGC && Verbose, true, gclog_or_tty); |
ysr@777 | 339 | GenMarkSweep::trace("3"); |
ysr@777 | 340 | |
ysr@777 | 341 | SharedHeap* sh = SharedHeap::heap(); |
ysr@777 | 342 | |
jrose@1424 | 343 | sh->process_strong_roots(true, // activate StrongRootsScope |
jrose@1424 | 344 | true, // Collecting permanent generation. |
ysr@777 | 345 | SharedHeap::SO_AllClasses, |
ysr@777 | 346 | &GenMarkSweep::adjust_root_pointer_closure, |
jrose@1424 | 347 | NULL, // do not touch code cache here |
ysr@777 | 348 | &GenMarkSweep::adjust_pointer_closure); |
ysr@777 | 349 | |
johnc@3175 | 350 | assert(GenMarkSweep::ref_processor() == g1h->ref_processor_stw(), "Sanity"); |
johnc@3175 | 351 | g1h->ref_processor_stw()->weak_oops_do(&GenMarkSweep::adjust_root_pointer_closure); |
ysr@777 | 352 | |
ysr@777 | 353 | // Now adjust pointers in remaining weak roots. (All of which should |
ysr@777 | 354 | // have been cleared if they pointed to non-surviving objects.) |
ysr@777 | 355 | g1h->g1_process_weak_roots(&GenMarkSweep::adjust_root_pointer_closure, |
ysr@777 | 356 | &GenMarkSweep::adjust_pointer_closure); |
ysr@777 | 357 | |
ysr@777 | 358 | GenMarkSweep::adjust_marks(); |
ysr@777 | 359 | |
ysr@777 | 360 | G1AdjustPointersClosure blk; |
ysr@777 | 361 | g1h->heap_region_iterate(&blk); |
ysr@777 | 362 | pg->adjust_pointers(); |
ysr@777 | 363 | } |
ysr@777 | 364 | |
ysr@777 | 365 | class G1SpaceCompactClosure: public HeapRegionClosure { |
ysr@777 | 366 | public: |
ysr@777 | 367 | G1SpaceCompactClosure() {} |
ysr@777 | 368 | |
ysr@777 | 369 | bool doHeapRegion(HeapRegion* hr) { |
ysr@777 | 370 | if (hr->isHumongous()) { |
ysr@777 | 371 | if (hr->startsHumongous()) { |
ysr@777 | 372 | oop obj = oop(hr->bottom()); |
ysr@777 | 373 | if (obj->is_gc_marked()) { |
ysr@777 | 374 | obj->init_mark(); |
ysr@777 | 375 | } else { |
ysr@777 | 376 | assert(hr->is_empty(), "Should have been cleared in phase 2."); |
ysr@777 | 377 | } |
ysr@777 | 378 | hr->reset_during_compaction(); |
ysr@777 | 379 | } |
ysr@777 | 380 | } else { |
ysr@777 | 381 | hr->compact(); |
ysr@777 | 382 | } |
ysr@777 | 383 | return false; |
ysr@777 | 384 | } |
ysr@777 | 385 | }; |
ysr@777 | 386 | |
ysr@777 | 387 | void G1MarkSweep::mark_sweep_phase4() { |
ysr@777 | 388 | // All pointers are now adjusted, move objects accordingly |
ysr@777 | 389 | |
ysr@777 | 390 | // It is imperative that we traverse perm_gen first in phase4. All |
ysr@777 | 391 | // classes must be allocated earlier than their instances, and traversing |
ysr@777 | 392 | // perm_gen first makes sure that all klassOops have moved to their new |
ysr@777 | 393 | // location before any instance does a dispatch through it's klass! |
ysr@777 | 394 | |
ysr@777 | 395 | // The ValidateMarkSweep live oops tracking expects us to traverse spaces |
ysr@777 | 396 | // in the same order in phase2, phase3 and phase4. We don't quite do that |
ysr@777 | 397 | // here (perm_gen first rather than last), so we tell the validate code |
ysr@777 | 398 | // to use a higher index (saved from phase2) when verifying perm_gen. |
ysr@777 | 399 | G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
ysr@777 | 400 | Generation* pg = g1h->perm_gen(); |
ysr@777 | 401 | |
ysr@777 | 402 | TraceTime tm("phase 4", PrintGC && Verbose, true, gclog_or_tty); |
ysr@777 | 403 | GenMarkSweep::trace("4"); |
ysr@777 | 404 | |
ysr@777 | 405 | pg->compact(); |
ysr@777 | 406 | |
ysr@777 | 407 | G1SpaceCompactClosure blk; |
ysr@777 | 408 | g1h->heap_region_iterate(&blk); |
ysr@777 | 409 | |
ysr@777 | 410 | } |
ysr@777 | 411 | |
ysr@777 | 412 | // Local Variables: *** |
ysr@777 | 413 | // c-indentation-style: gnu *** |
ysr@777 | 414 | // End: *** |